1. Technical Field of the Invention
The present invention relates to an idle stop system mounted in a vehicle.
2. Related Art
Recently, with an increasing need for reducing fuel consumption, for example, to reduce emission of CO2 or to save the cost of fuel, a technique associated with so-called idle-stop control has been developed. It is known that, under idle-stop control, i.e. in an idling mode, the engine is automatically stopped when predetermined stop conditions are met, and then, the engine is automatically restarted when predetermined restart conditions are met. Performing idle-stop control effectively contributes to the reduction of fuel consumption.
In a vehicle equipped with a manual transmission, there is concern that an engine start failure may be caused in restarting the engine from an automatically stopped state, if a clutch-engaging operation is performed before completion of the engine start.
In order to mitigate the problem mentioned above, JP-A-2000-018060 discloses a technique related to an idle stop system mounted in a vehicle. According to the technique, the idle stop system performs three control processes which are: transmission control that controls the automatic transmission; automatic stop control that automatically stops the engine when predetermined stop conditions are met; and automatic start control that automatically starts the engine when predetermined start conditions are met.
In the idle stop system disclosed in this patent document, the automatic stop control is configured to be cancelled when the time spent after the engine start is less than a preset time period, or when the number of the automatic start controls is equal to or more than a preset number of times. Meanwhile, by performing the transmission control on the automatic transmission, the clutch is prevented from achieving engagement while the engine start is incomplete, which would otherwise have been caused by human error. Thus, the engine start and the start of running after the automatic engine stop have been configured to be smoothly conducted.
However, in a vehicle system equipped with a manual transmission, the existing techniques including one disclosed in JP-A-2000-018060 mentioned above cannot provide a fundamental resolution for the engine start failure at the time of restarting the engine, which failure is caused by performing clutch engagement before the engine start is complete.